I would seek other web developers at any number of public forums like OReilly Ignite, BarCamp, DevHouse, etc.<p>For informal UI testing, you can even go to any coffee shop, show people your work, and ask them what they think. Often you can benefit by seeing a virgin user who didn't understand that action X lead to result Y.<p>You could also quantitatively test your choices by pushing a different UI on some small percentage of users, and see how it affects performance or things like signing up active users.<p>Certainly rely on your peers, but the best mentor is need. Solving a problem teaches so much.